This work is a study of the metabolism of purine bases, nucleosides and nucleotides with emphasis on determining the pathways of purine salvage in the formation of inosinic, adenylic and guanylic acids. The aim of the study is to specifically identify and quantitate these individual pathways so that deviations from normal can be determined in various pathologic states in which primary and secondary hyperuricemia exists. Methodology will include the use of tissue culture, human lymphocytes exposed to labeled purine bases. Radioisotopic and chemical analysis of the nucleotides, RNA and DNA of the cultured cells will be done at appropriate intervals to determine pathways and rates of incorporation inter-conversion and salvage of the cellular purines.